基于微观破损机理的胶结砂土三维本构模型研究  

Three-dimensional constitutive model for cemented sands based on micro-mechanism of bond degradation

作　　者：张伏光 蒋明镜[4,2,3] ZHANG Fu-guang;JIANG Ming-jing(School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongii University,Shanghai 200092,China;Department of Civil Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]石家庄铁道大学土木工程学院,河北石家庄050043 [2]同济大学地下建筑与工程系,上海200092 [3]同济大学岩土及地下工程教育部重点实验室,上海200092 [4]天津大学建筑工程学院,天津300072

出　　处：《岩土工程学报》2018年第8期1424-1432,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金重点项目(51639008);国家自然科学基金项目(51579178)

摘　　要：在岩土破损力学和临界状态土力学框架内,遵循宏微观土力学的研究思路,建立了胶结砂土三维本构模型。定义与重塑砂土屈服面几何相似但尺寸扩大的胶结砂土屈服面;采用经三维离散元验证的Lade-Duncan强度准则作为临界状态强度面;基于胶结材料微观力学理论并结合三维离散元模拟结果,获得具有微观力学机制的胶结破损规律;将胶结破损规律引入到重塑砂土的硬化规律和流动法则,得到胶结砂土的硬化规律和流动法则。将该本构模型应用于人工制备胶结砂土室内常规三轴压缩试验和等平均应力真三轴试验的模拟,初步验证了该模型的适用性。Based on the framework of breakage mechanics for geological materials and the critical-state soil mechanics, a three-dimensional（3-D） constitutive model for cemented sands is proposed following the research idea for macro-and micro-mechanical soil mechanics. A yield surface for reconstituted sands is improved for the cemented sands by enlarging the surface size. To consider the behaviors of shear strength in the 3-D space, the Lade-Duncan strength criterion, validated by simulations of 3-D distinct element method（DEM）, is used as the critical-state strength surface. A degradation evolution for bond is obtained from 3-D DEM specimens based on the micro-mechanics theory for cemented materials and the simulated results of DEM. By introducing the degradation evolution for bond, the hardening law and flow rule for reconstituted sands are modified and applied for cemented sands. The proposed model is preliminarily verified by predicting the mechanical behaviors of artificially cemented sands in the conventional triaxial compression tests and true triaxial tests with constant mean stress.

关 键 词：胶结砂土 微观机理 离散元 本构模型 

分 类 号：TU43[建筑科学—岩土工程]